The present invention relates to an adaptable solid hybrid rocket system which combines solid and hybrid propulsion for providing emergency escape propulsion or orbital injection propulsion to a reusable spacecraft such as a manned spacecraft.
Future generations of space vehicles will have a manned crew transfer vehicle which rides on a reusable launch vehicle. The crew transfer vehicle may be injected into orbit to eventually dock with a space station. The crew transfer vehicle requires a crew escape system to supply propulsion and control for the crew to escape from the reusable launch vehicle, as directed by a health monitoring system, under each and all reusable launch vehicle ascent flight phases.
The crew escape system must be capable of very rapid crew transport away from impending danger. The time period from health monitor sensing of a problem to the crew escape system fire-signal may be on the order of one second. Consequently, the crew escape system propulsion must provide very high thrust coupled to very high control maneuverability immediately upon command. High thrust is needed for the first few seconds and must be followed by a longer period of sustained propulsion. Previous propulsion applications with a similar set of requirements have always depended on solid rocket propulsion to generate immediate/very high thrust. Alternate propulsion systems, i.e. liquids, hybrids, gels, require significantly longer time duration to achieve steady-state thrust, and do not achieve the high thrust/weight ratios inherent to solid rockets.
A properly designed and produced reusable launch vehicle/crew transfer vehicle will not experience the type of failure that would require a crew escape system very often, perhaps 0.1% of the time. Consequently, a crew escape system solid propulsion system would in theory be used only rarely. Furthermore, the crew transfer vehicle requirement to minimize explosives, while docked with a space station, does not allow a solid propulsion system onboard. Jettisoning the crew escape system solid propulsion system after all potential escape situations have subsided, and prior to orbital injection, clearly represents an inefficient and expensive approach, as in 99.9% of the time, the solid propulsion system would be thrown away having served no function.
Therefore, a launch vehicle is needed which has a propulsion system which generates immediate, high thrust and has control maneuverability, and which also is used as part of every mission prior to orbital injection and/or space station docking.
Accordingly, it is an object of the present invention to provide an adaptable solid-hybrid rocket propulsion system.
It is a further object of the present invention to provide a propulsion system which maintains the high thrust and maneuverability required for crew escape system operations and incorporates propulsion flexibility to support orbital injection propulsion as part of each mission.
It is yet a further object of the present invention to provide a propulsion system as above wherein a flight crew is not exposed to the high acceleration required for escape on each and every mission.
The foregoing objects are attained by the adaptable solid-hybrid rocket propulsion system of the present invention.
In accordance with the present invention, a rocket propulsion system broadly comprises a casing defining a chamber, a solid propellant system positioned within the chamber for generating one of escape propulsion during an emergency portion of an ascent flight and orbital injection propulsion during normal flight operations and a sustain propulsion system communicating with the chamber for sustaining the emergency escape propulsion during said emergency portion of the ascent flight and orbital injection thrust during the normal flight operation. The secondary propulsion system may be a hybrid solid fuel grain and liquid oxidizer system or a liquid fuel and liquid oxidizer system.
Other details of the adaptable solid-hybrid rocket propulsion system for crew escape and orbital injection propulsion, as well as other objects and advantages attendant thereto, are set forth in the following detailed description and the accompanying drawings wherein like reference numerals depict like elements.